|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
08 Jan 2021, 20:12
Kudos
Bookmarks
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
45%
(medium)
Question Stats:
71% (02:34) correct
29%
(02:26)
wrong
based on 194
sessions
History
Date
Time
Result
Not Attempted Yet
Two cars, which are x miles apart, take u minutes to pass each other when they are moving towards each other, and v minutes to meet each other when they are moving in the same direction. Find the ratio of the rate of the slower car to that of the faster car.
A. \(\frac{u}{v}\)
B. \(\frac{u}{v-u}\)
C. \(\frac{v−u}{v+u}\)
D. \(\frac{u}{v+u}\)
E. \(\frac{v}{v+u}\)
A. \(\frac{u}{v}\)
B. \(\frac{u}{v-u}\)
C. \(\frac{v−u}{v+u}\)
D. \(\frac{u}{v+u}\)
E. \(\frac{v}{v+u}\)
08 Jan 2021, 21:39
Kudos
Bookmarks
DisciplinedPrep
Let the speed of car be a and b.
Two cases are given
1) Cars moving towards each other: Distance traveled = d, and speed will be the combined speed of the two cars = a+b
So, \(\frac{d}{a+b}=u......d=u(a+b)\)
2) Cars moving in same direction: The faster car has to cover the distance between them to catch up with the slower car.
Distance traveled = d, and relative speed = a-b
So, \(\frac{d}{a-b}=v.....d=v(a-b)\)
Equating the values of d
\(u(a+b)=v(a-b)..........ua+ub=va-vb........va-ua=vb+ub\)
\(a(v-u)=b(v+u)............\frac{a}{b}=\frac{v+u}{v-u}...\ \ or \ \....\frac{b}{a}=\frac{v-u}{v+u}\)
C
07 Apr 2024, 18:55
Kudos
Bookmarks
Hi chetan2u, thank you for your answer. I have a question that how we know the distance two cars travelled meet moving towards and same direction are equal? I was thinking that distance travelled of both cars moving towards each other is x, but distance of cars meeting when same direction would be larger than x. Thank you very much!
